[RE-wrenches] Landing into a sub-panel without a main service

[Pekka Laine]

Thank you for all the great interest and the comments on this topic. Here are some more details on this project:
 
1. 200 A fused Zinsco Main Switch at the service entrance (45 years old) 
2. Inside the house Square D Split-bus "Main" panel with two 100 “Mains” fed by 1/0 wire from the outside 200A Main fused switch
3. Next to it Murray 100/125A Sub-panel (Newer, some damage) 
4. Outside Zinsco 125A Sub-panel 
5. In the pool room 125A Sub-panel 
6. In the garage Murray 125 A Sub-panel (newer, looks OK) 

The utility is SDG&E, so no line or load side taps are usually allowed.  On another project, we have previously replaced a similar type fused main switch with a Eaton Solar Ready Loadcenter with 225A rated buss and 200A main breaker in order to be able to backfeed max. 70 A of PV. I am leaning towards doing the same on this one....

In this case, I will recommend the customer to upgrade/replace the old Square D split bus panel and items 3 & 4. as well. Any other suggestions are welcome.

Happy Holidays!

Pekka Laine

President
Photon Solar Power Inc.
www.PhotonSolarPower.com
Cell. 760-556-8170
Toll Free 888-SUN-ACDC
CA Lic. #933648
NABCEP Certified PV Installer # 032611-174